PROGRAM SUMMARY/ABSTRACT The overall objective of this project is to increase the pool of under-represented South African scientists conducting rigorous, interdisciplinary health social science research focused on better engaging men in the HIV continuum of prevention, treatment and care. Research regarding men, masculinities and HIV is a critical element of improving the country?s response to HIV, as men have consistently poorer rates of engagement with HIV services and worse antiretroviral treatment outcomes. This revision application enhances the work already underway in our existing project that combines epidemiological and social science approaches to examine the movement of men through the HIV care cascade in Cape Town. This revision project will extend this work by training, supporting and mentoring researchers from under-resented groups and historically disadvantaged institutions. The project is designed to provide intensive support and mentoring to two early-career researchers from under-represented groups who will also serve as Co- Investigators on the application. To facilitate independence, these Co-Investigators will be responsible for leading, designing and implementing two mixed methods comparative case studies in Cape Town and Johannesburg exploring the factors affecting the delivery, uptake and impact of services for HIV-positive men in South Africa. During this process they will be closely supported by the South African MPI and another experienced Co-Investigator. In addition, bi-directional exchanges with our US partners at Brown University will facilitate these core trainees? access to valuable upskilling through appropriate courses and mentoring, while also providing opportunities to impart their own experiences and insights to MPH and PhD students. This project also seeks to connect and catalyse collaborations among a wider group of under- represented scientists and those working at HDIs. Core trainees will be tasked with designing and co- convening short courses to train this broader group in key social science theoretical and methodological approaches, thereby building critical research capacity in inter-disciplinary health social science. Finally, we will work to build the groundwork for more cohesive, productive, interdisciplinary scholarship around men and HIV by setting up a national network of researchers and other stakeholders engaged with this issue. We will sustain the early stages of this network by holding multiple network meetings during the two project years. The ultimate focus of our project is on growing the pool of researchers who can improve our understanding of the behavioural and social factors that contribute to ART linkage and retention among men. The activities above will also address some of the entrenched barriers to building a diverse research workforce in South Africa by maintaining a focus on under-represented scientists at various levels.